1. Field of the Invention
This invention relates to gas lift apparatus and more particularly to side pocket mandrels for use in gas lift wells.
2. Description of the Prior Art
Side pocket mandrels with orienting means therein for orienting a kickover tool used in installing well flow control devices in or removing them from their offset receptacles have been used for many years. Side pocket mandrels and kickover tools therefor have been supplied by a number of suppliers in the industry. Kickover tools from one supplier may not work well in the side pocket mandrels of another supplier even though such kickover tool may have been intended for use in such side pocket mandrel. It has been desirable to provide a side pocket mandrel which would be compatible with virtually any kickover tool designed for use with such mandrel and to minimize difficulties arising from such mismatching.
The orienting means in side pocket mandrels have been in the form of a sleeve surrounding the bore through the side pocket mandrel, this sleeve being provided with a pair of symmetrical guide surfaces generally helical in shape leading from a point at the lower end of the sleeve upwardly to the lower end of a longitudinal orienting slot. In some cases where the sleeve provides orientation only, this slot may pass completely through the sleeve. In other mandrels the slot may be provided with a shoulder, and in some cases this shoulder completely blocks the slot. Such shoulder at the upper end of the slot is utilized in activating a kickover tool after it has first been oriented.
Kickover tools of the orienting type are provided with an orienting key sufficiently narrow to enter the orienting slot in the orienting sleeve and have an abrupt upwardly facing shoulder thereon. When this abrupt shoulder engages the orienting sleeve, it will follow one of the guide surfaces causing the kickover tool to rotate about its longitudinal axis until the key becomes aligned with and enters the slot, thus orienting the kickover tool with respect to the side pocket mandrel, that is, positioning the kickover tool for installing a device in the offset receptacle of the side pocket mandrel. In some cases, as where wireline equipment is used, the same abrupt shoulder of the orienting key also engages the shoulder in the slot, and further movement of the kickover tool causes it to be activated such that a portion thereof is shifted laterally into alignment with the offset receptacle of the side pocket mandrel.
Kickover tools are commonly run into wells and removed therefrom by conventional wireline equipment or by conventional pumpdown operations. In the latter, the kickover tool and a string of pumpdown tools including piston units are moved by fluid pressure into and out of the well by circulation of fluids through the well. Whether the kickover tool is run by wireline or by pumpdown methods, it is sometimes difficult to control the velocity of the kickover tool with respect to the side pocket mandrel. Thus, it often occurs that the kickover tool moves through the side pocket mandrel at excessive velocities. This may be due to the drag of the tools in the well tubing during pumpdown operations and also due to the fluid bypass through the kickover tool. These may cause the tools to lodge momentarily in tight places in the tubing and then move quickly until stabilization occurs and normal velocity is restored. Similarly, in wireline operations (the wireline being elastic), such a condition can occur. This condition can be further aggravated where the wireline reel is mounted on a floating vessel which tosses about on the water's surface relative to the well which is stationary with the earth. When the kickover tool moves too fast relative to the side pocket mandrel, its orienting key may fail to enter the slot of the orienting sleeve. One particular type or orienting key has failed frequently and caused considerable difficulty. When this type of key engages one of the guide surfaces on an orienting sleeve while the kickover tool is moving rapidly with relation thereto, considerable rotational force is applied to the kickover tool. In such case, the orienting key may strike the juncture of the opposite guide surface and the opposite wall of the slot in such manner that it causes the orienting key to retract momentarily and pass through the sleeve without ever orienting the kickover tool.
The present invention overcomes such difficulty in a manner which will be hereinafter explained.
A search of the prior art was made, and the following U.S. patents were located, each of which illustrates an orienting sleeve in a side pocket mandrel.
______________________________________ 2,942,671 3,807,498 4,034,806 2,948,341 3,827,489 4,051,895 3,353,607 3,827,490 4,066,128 3,581,818 3,837,398 4,103,740 3,610,336 3,874,445 4,106,563 3,727,683 3,876,001 4,106,564 3,732,928 3,889,748 4,135,576 3,741,299 3,891,032 4,146,091 3,741,303 3,965,979 4,197,909 3,752,231 4,002,203 4,239,082 3,788,397 4,031,954 4,271,902 3,796,259 4,033,409 4,294,313 ______________________________________
Included in the above list are three patents which are considered exemplary of the types of side pocket mandrel orienting sleeves of which the present invention is an improvement. The list also includes a fourth patent which illustrates and describes a kickover tool having an orienting key of the type which has been associated with the failures discussed hereinabove.
U.S. Pat. No. 2,942,671 which issued to Harry B. Schramm on June 28, 1960 discloses a side pocket mandrel with an orienting sleeve therein, the orienting sleeve having a pair of guide surfaces which lead to a longitudinal orienting slot which passes completely through the sleeve.
U.S. Pat. No. 2,948,341 which issued to John V. Fredd on Aug. 9, 1960 discloses a side pocket mandrel having an orienting sleeve therein which is provided with guide surfaces leading to a longitudinal orienting slot which passes completely through the sleeve, but the sleeve is further provided with shoulder means located in the slot.
U.S. Pat. No. 3,827,490 which issued to Howard H. Moore, Jr. and Harold E. McGowan, Jr. on Aug. 6, 1974 discloses a side pocket mandrel having an orienting sleeve therein having a pair of guide surfaces leading to an orienting slot and a trip shoulder at the end of the slot which completely blocks the slot. These three patents are typical of the types of orienting sleeves which are disclosed in the other patents listed above.
U.S. Pat. No. 3,876,001 which issued to William B. Goode on Apr. 8, 1975 illustrates and describes a kickover tool for use in side pocket mandrels which are equipped with orienting sleeves such as that just mentioned with respect to U.S. Pat. No. 3,827,490. This kickover tool is equipped with an orienting key having a portion thereof protruding from a window and presenting cam surfaces which would tend to cam the key inwardly toward retracted position when meeting with obstructions in the well tubing. This key has an upwardly opening radial slot at its upper end and has a filler piece pivotally mounted in the slot. This filler piece is shear-pinned in place to releasably hold it in the position shown, in which position the filler piece presents an abrupt upwardly facing shoulder to engage the guide surfaces and trip shoulder of an orienting sleeve. Upon shearing the shear pin, the filler piece becomes inoperative, and the key will thereafter pass shoulders or obstructions with readiness because of the key's cam surfaces mentioned earlier camming the key toward retracted position upon encountering obstructions in the well tubing.
There was not found in the prior art patents a side pocket mandrel having a longitudinal orientation slot and a pair of guide surfaces therebelow directed upwardly toward the lower end of the slot but intersecting the slot at different levels which are spaced apart longitudinally. Neither was there found a side pocket mandrel having an orienting sleeve with a longitudinal orientation slot therein and a single guide surface therebelow directed upwardly toward the lower end of the slot from a point at the lower end of the orienting sleeve via a helical path and making substantially a full revolution before intersecting the slot.
The present invention overcomes the problems and shortcomings discussed hereinabove by providing side pocket mandrels having orienting sleeves therein with guide surfaces of a novel form which eliminate malfunctioning as described above and thus saves much time and money.